Archimedes Laboratory Project™
Puzzles & Mental Activities that Enhance Critical and Creative Thinking Skills

Using just basic geometry prove that: a·a’=b·b’+c·c’
Démontrer que: a·a’=b·b’+c·c'
Dimostrare che: a·a’=b·b’+c·c'

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Solution: a’ = x + y By similarity: x/b’ = b/a => ax = b·b’ y/c’ = c/a => ay = c·c’ Then: a(x + y) = b·b’ + c·c’ = a·a’ (see picture below) Please spread the word about the Sunday Puzzle!